Dynon needs your help: 5.4 GPS Nav Source Dropouts

BigJohn

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May 25, 2011
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27
An update here - we're going to be taking another crack at a fix for this issue.........

See my post in the other thread for my experience with the beta software. Thanks for continuing to look at this issue. That's good customer support!
 

Roger_Lee

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Aug 1, 2006
Messages
68
Just an FYI.
Several different aircraft have had issues with the AP/compass and Skyview headings and matching up. It has been found to be that metal parts near the remote compass are magnetized. These need to be degaused.
 

juhee

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Jan 22, 2012
Messages
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Same, loses NAV Source several times in 30 min flight. This is pretty darn frustrating. Its seems as though it couples in NAV mode and wants to work but then goes lame searching 90 degrees either side of course. Even after being on course it will just start meandering around in all modes, including heading. Then there are times it works a few minutes. Or is it really working? Please explain what the roll servo slipping indication looks like and where. How can I tell if I have SV52s by looking on the screen. Is it possible slippage is the problem even with 52s? Maybe I need to arm variant and linkage hole. The airplane is a RANS S-19 ELSA.. Sorry for all the questions, I just searching for a clue.

I found it...success....My Servos were 2007 mfg and the log data I sent in to Dynon indicated slippages...they changed them out for me with new restored ones and they really work as designed....I am so happy flying around with confidence by my Ap74 heading and Alt bugs...what a joy after a year and half chasing clues...It took Garmin to add data sentences to my GDU375 so it could couple with the Dynon Ap74 and D100....And Dynon beta 5.5v....with the new servos....I'm really happy....












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mdyoung

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Oct 14, 2012
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I’m having the same problem with AP dropping NAV.  Originally had Garmin 495 installed.   Just replaced 495 with Garmin Aera 550 and Garmin GDL39.   AP NAV drops with both GPS units.

Here is how it’s configured.

Garmin Aera 550 is directly connected to GDL-39.  Dynon D180 is connected to GDL-39 using serial pass through connection (TxB-Orange Wire out from GDL-39 connects to D180).  Also have ICOM A210 Comm Radio connected to TxB from GDL-39.

GPS interface is setup as “Aviation In/NMEA & VHF Out” Baud “9600”.

Another problem that I have experienced with Dynon AP is getting ERR on both PITCH and ROLL.  System seems like it randomly loses power to the servos – Can not find any wiring / connectivity issues so not sure what the source of the problem is…

Any help on the NAV drop issue and the ERR issue would be appreciated.
 

dynonsupport

Dynon Technical Support
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Mar 23, 2005
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So the NAV dropout thing is the "known problem", and we should have new software to test another attempt at a fix soon (no promises on a date, R&D ongoing).

ERR means that the servos have gone away, usually because of a wiring issue or loss of power. Do you notice it when the AP is not engaged, or only when it's actually engaged. How long does it persist? Does normal status come back after some time?
 

mdyoung

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Oct 14, 2012
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Had a chance today to tap the Tx wire from the GPS to EFIS. Here is a snapshot of what we found... Starts with clearn Tx data stream then random garbage then back to clean data stream. Everytime the random garbage was recorded in the data stream, the AP NAV drops and the CDI drops. Will email complete log file. Decoupled Dynon from GPS Tx and still had garbage in data stream. Any ideas?


$PMRRC0534OK66
$PMRRC0534KP67
$PMRRC0530GT63
$PMRRC053<JV74
$PMRRC0531IL5>
$PMRRC0533KP66
$PMRRC0533OK65
$PMRRC053:J854
$PMRRC053:KJ67
ÿ8c{°BJKùZc­$(GùÒËzÊRCP"Rì j
c¶)þM¡Xz`àóÙòú[
ãÊEåÛ
oÛÅÊ

J?½ä
E÷ÒþgCJ?ò)B=b©rk¦hÂJhþZkç)R1ZOkæ0Ä÷ILÿÆÏZÚBCÌÊl#}?ÃKbaÕb(bÜSµÿS¨èy22SæÓ­ÿuäyôÜrCJþ9=i3ÿfc§ÿ$GPGSV,3,2,10,12,14,319,28,17,53,051,16,20,17,047,00,27,28,267,00*76
$GPGSV,3,3,10,28,37,141,18,51,45,213,28*74
$GPGLL,3354.2851,N,08718.8110,W,171127,A,A*57
$GPBOD,126.0,T,128.6,M,KBHM,*43
$GPBWC,171127,3333.8332,N,08645.1377,W,126.0,T,128.
 

dynonsupport

Dynon Technical Support
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Mar 23, 2005
Messages
13,227
We got your email. Thanks for that! We'll followup with any further questions via that email thread.
 

mdyoung

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Oct 14, 2012
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4
Garmin support reviewed the data stream files and recommend grounding the orange/white (RxB) wire from the GDL-39.  This appears to have corrected the problem.  Attached is the revised wiring diagram that was sent..
 

Attachments

  • Aera_550_GDL_39_interface.bmp
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rich1

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Feb 29, 2012
Messages
7
Dynon,
I down loaded the new 5.5RC1 software for my D10A EFIS/AUTO PILOT.
I flew 2 flights, a total of 1.5 hrs.
          NO DROP OUTS!!!
Im using a Aera 500 with a GLD 39.
I would have 3-5 droup outs before the new soft ware.
I will post later after several more hours.
Rich
 

Foxflier

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Joined
Dec 3, 2010
Messages
33
Sadly, the problem has not gone away.

I had the opportunity to fly 4 hrs yesterday on AP and I had 3 dropouts.  The big problem is that after two of the dropouts it took up to 15 mins before the GPS nav source became available again to re-sync.  The AP reverted to TRK mode and the GPS was clearly still providing info for TRK but the NAV mode selection went away for an extended period. It used to drop out more often but NAV mode would reappear and could be reset relatively quickly (most of the time immediately).

I am so disappointed!  I love my AP...when it works...

Just to confirm this is with the 5.5RC1 firmware.

Why can't we get this fixed???
 

Dynon

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Woodinville, WA
So that's definitely not characteristic of the problem that we've seen in the field. It's usually a momentary lapse in data that results in dropdown into hdg mode, which can then me immediately re-engaged into either trk or nav mode.

Any chance your 696 has a software update available for it? What are your nmea settings on both ends?
 

Foxflier

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Dec 3, 2010
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Latest 6.5 firmware on the 696.

Prior to the update to 5.5RC1 (last 18 months) I would get a NAV source failure message and be able most of the time to immediately go to the source menu and re-select NAV.

Now I get the NAV source failure message, AP defaults to TRK mode, I lose the NAV source menu selection (as well as loss of the CDI) with only TRK and HDG available.  GPS still shows up and TRK works but the NAV menu selection is gone.  Once during the three losses the NAV source selection re-appeared immediately but the other two times it took between 5 and 15 minutes for NAV source to reappear.

The 696 is set to GTX TIS-A In / NMEA & VHF Out at 9600 baud.  The GPS transmit line is connected to Pin 19 of my EMS D120 DB25.  The EMS serial is set to default.
 

Dynon

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What happens if you disengage and reengage the AP? Does that change anything?

When you're not getting the NAV mode available (after the failure), does the HSI on the Dynon still show a valid CDI?
If it doesn't, is there still a valid direct to or active flight plan available to navigate from from the 696?
If yes, what happens if you cancel navigation and reenable it on the 696? Does that bring back the selectability of the NAV option on the AP?
 

Foxflier

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Dec 3, 2010
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Disengaging and re-engaging the AP has no effect. The CDI is gone when NAV disappears. The flight plan from from the 696 remains and I've tried terminating and changing the 696 flight plan to see if that had an effect to no avail. I tried all this during the the second 10 min loss of NAV availability. I finally just flew TRK and checked back on the source page every few mins until NAV reappeared.
 

dynonsupport

Dynon Technical Support
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You are seeing a very different issue than the one we are attempting to fix. The general issue is that the AP switches from NAV to TRK mode, but the pilot never sees the CDI go away, and pressing NAV takes them right back. The dropout is very quick.

Your situation of missing data for minutes on end seems to be unique. If the CDI is not displayed, then this is not an AP issue, it's a general connection issue, and we need to troubleshoot that before we worry about the AP.

First and foremost, what is connected to the D100? You mention the 696 is connected to the D120, so I wonder what is on the D100.

What firmware is on the 696? What mode is the serial port output in for advanced NMEA setup?

Any other changes you can think of between it working and not besides the update to 5.5RC1? I note you would have needed to disconnect the 696 from the D120's serial port in order to upgrade the D120, any chance a mechanical wiring issue was introduced?
 

Foxflier

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Dec 3, 2010
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You are seeing a very different issue than the one we are attempting to fix. The general issue is that the AP switches from NAV to TRK mode, but the pilot never sees the CDI go away, and pressing NAV takes them right back. The dropout is very quick.

Your situation of missing data for minutes on end seems to be unique. If the CDI is not displayed, then this is not an AP issue, it's a general connection issue, and we need to troubleshoot that before we worry about the AP.

First and foremost, what is connected to the D100? You mention the 696 is connected to the D120, so I wonder what is on the D100.

What firmware is on the 696? What mode is the serial port output in for advanced NMEA setup?

Any other changes you can think of between it working and not besides the update to 5.5RC1? I note you would have needed to disconnect the 696 from the D120's serial port in order to upgrade the D120, any chance a mechanical wiring issue was introduced?

I have a D120 and a D100.  Per the Dynon D120 and D100 installation manuals my GPSMAP 696 is connected to the EMS via the EMS DB37 pin 19.  I mistakenly wrote DB25 above but it's a DB37.  Nothing is connected to the EFIS DB25 serial receive Pin 22.  I've asked the question before in another thread as to whether connection via the EMS as directed could have any effect regarding this issue.  Reference the EMS installation manual page 4-4 regarding installation of both a D100 and D120.

The latest Garmin V6.5 firmware is on the 696.  The 696 serial output is set to NMEA & VHF out at 9600 per my above reply.  The only difference between now and prior to 5.5RC1 is that the recovery of NAV takes longer. 

I'm not understanding why you indicate it's a different problem than the original lost NAV source.  I've experienced the exact same symptoms over the past 18mos of operation before 5.5RC1 -- it just recovered much quicker before 5.5RC1 (most of the time almost immediately, I'd just have to reselect NAV).  I have less dropouts now, but the dropouts recover much slower.

BTW, I do NOT have to disconnect the EMS to update firmware since the Aux Serial Input is utilized....
 

Foxflier

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Dec 3, 2010
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A quick update...after flying 4hrs this weekend I believe I can say my AP is now working properly.  I experienced no NAV source dropouts.  :)

As advised above I went in and reviewed the communication settings in my D100 and found that the baud rate and comm type were both set to Auto (default setting).  I thought I had changed the settings when I installed the EFIS in early '11 but I'm not going to swear on it.  I changed settings to 9600 and NMEA and it appears that solved my recent NAV dropout and subsequent delay of re-sync problem.  I was apparently suffering from a combination issue.  I'm assuming the EFIS was getting hung up trying to auto sync with my 696 after a momentary data loss.

I believe the 5.5RC1 does fix the intermittent NAV source dropout issue as my AP now seems to be reliable.

Thanks for continuing to work this one Dynon!

Ted
 

rich1

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Feb 29, 2012
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Flying for 35hrs with the new 5.5RC1 software and not one AP drop out. I have a D10A,EMS 10, AERA 500 hard wired to GDL39.
However I noticed an occasional dropout (about 1sec.) of the GPS magenta data on the HSI page. Does not affect the AP or anything else that I can tell.
For your data point Dynon.
Rich
 
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